Fire and cattle grazing on wintering sparrows in Arizona grasslands

Published source details Gordon C.E. (2000) Fire and cattle grazing on wintering sparrows in Arizona grasslands. Journal of Range Management, 53, 384-389.
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This study is summarised as evidence for the following.

	Action	Category
	Employ grazing in natural grasslands Action Link
	Use prescribed burning on grasslands Action Link

Employ grazing in natural grasslands

A paired site comparison in 1997-1999 at the Audubon Research Ranch and Davis Pasture in Arizona, USA (Gordon 2000), found no consistent effects of grazing grasslands on Ammodramus sparrow species. Baird’s sparrows A. bairdii were more abundant on the grazed than ungrazed area in 1997 (1.3 vs. 0.5 captures/plot/day) but did not differ significantly thereafter (0.4-1.9 vs. 0.8-1.3). Grasshopper sparrows A..savannarum were more abundant on the grazed area in 1997 (4.7 vs. 0.44), but more abundant on the ungrazed area in 1998 and 1999 (1.3-4.8 vs. 3.2-15.0). The Audubon Research Ranch (3,160 ha) was ungrazed by livestock since 1968, the Davis Pasture (1,501 ha) had moderate grazing pressure (645-1,387 animal unit months/year).
Use prescribed burning on grasslands

A replicated, controlled before-and-after study in 1997-1999 in six semi-desert grassland plots at Buenos Aires National Wildlife Refuge, Arizona, USA (Gorden 2000), found that the population responses of five wintering sparrow species to a prescribed spring burn varied between species. Over the three years, vesper Pocecetes gramineus and savannah Passerculus sandwichensis sparrow populations increased in three burned plots, whilst Cassin's sparrow Aimophila cassinii populations decreased. Grasshopper sparrow A. savannarum increased up to two years post-burn. Baird's sparrow Ammodramus bairdii had consistently low abundance (<0.7/plot).